Hi
I'm looking for a reputable forum member who would play the third signer on a 2/3 multisig address. I'm trying to buy BTC with Paypal: https://bitcointalk.org/index.php?topic=3643378

Your role would be an independent entity who would have to decide who gets the funds in case of a disagreement. All you have to do is not loosing your private key for that multisig address. You would get 1% of the transferred BTC at the end of the deal. I'm planing on doing this regularly in the region of up to 3000$/180days, but the first transactions would be of low value (e.g. 50$), to grow confidence. In the expected case you only have to provide your public multisig key once and do nothing besides receiving your 1% share. Only in case of a dispute you will have to step in.

Reputable is someone with a positive trust score, more than 1 year registered, more than 100 messages and active profile.

Dispute process
As the third signer your most important task is not loosing your private key (or the generation seed) for our shared address. For each deal you received the details at the beginning. A deal is me buying x BTC for y USD from seller. In case of a dispute I will give you access to my Paypal account where you can make an informed decision. If that doesn't happen or there is any doubt err on the side of the seller.